Steam-engine air-pump.



No. 825,950. PATENTED JULY 1'7, 1906.

W. WEIR.

STEAM ENGINE AIR PUMP.

APPLIOATION FILED SEPT. 28. 1905.

K017671655 e s:

ZO'cZZzLa C0 27* W @iQ rm Ne PETEFS row. WASHINUYON. n, c

UNITED STATES PATENT oFFIoE.

STEAM-ENGINE AIR-PUMP.

Specification of Letters Patent.

Patented July 17, 1906.

Application filedSeptember 28, 1905. Serial No. 280,492.

To all whom it may concern:

Be it known that I, WILLIAM WEIR, a subject of the King of the United Kingdom of Great Britain and Ireland, residing at Oathcart, Renfrewshire, Scotland, have invented certain new and useful Improvements in Steam-Engine Air-Pumps, of which the following is a specification.

My invention has for its object by a novel construction and combination of parts to improve the working of vertical air-pumps of the single-acting type when these are driven independently and directly by the piston-rods of steam-cylinders, to overcome the defects in working of this type of pump due to the unequal and unbalanced loads on the air-pump piston on its u ward and downward stroke, and to diminis the height and generally secure compactness in the design of such air-pumps.

This invention is applicable to single vertical direct-acting air-pumps driven by steamcylinders fitted with any type of actuating steam-valve.

According to my invention and as illustrated in vertical section in the accompanying drawing, which shows a single direct-acting air-pump fitted with my improvements, I arrange on the under side of the main steam-cylinder A a prolongation thereof A, but of less diameter, having its lower end open. In this smaller or differential cylinder A works a trunk or plunger B, which is attached to the maincylinder-piston O and rod D. The top side a of the main steam-cylinder A is in communication with the steam and exhaust ports 6 of the steam-actuating valve E. The under side of the main steamcylinder piston at a is arranged to be always in communication with the steam-supply pipe, as by a branch F, so that the under side of the main piston O is always subject to the working steam-pressure.

The action of the pump when fitted with this improvement is as follows: On the upward or discharge stroke of the air-pump G the under side of the main piston C, less the area of the differential plunger B, is subject to the steam-pressure and is available for actuating the pump. On the downward stroke the upper side of the main piston O and the under side also, less the area of the differential trunk or plunger B, are subject to the steam-pressure. There is therefore only an area equal to that of the differential trunk or plunger B available for actuating the pump, and the size of this differential plunger is accordingly arranged to permit the pump G to make its downward stroke at the speed desired.

For the purpose of securing greater oompactness and decreasing the height of the pump the pump-cover-i. e., the cover H of the pump-casin is arranged and constructed to support tIie main and differential cylinder A A and to form a closed communicating chamber h between the open end of the differential cylinder and the portion of the air-pump above the discharge-valves J.

By this construction for an air-pump working with surface condensers any leakage of steam from the under side of the main cylinder A past the differential plun er B will be absorbed by the water whic the pump is pumping durin its passage from the air-pump G, and as t s water is generally used for feeding boilers the arrangement will prevent any heat loss.

The movement of the steamvalve E, which may be the auxiliary valve of any well-known type of valve-gear, is secured by attaching to the air-pump bucket G a supplementary rod K, passing through a gland L on the pump-cover H, working on .a guide L, attached to the steam-cylinder A, and actuating through a cross-head M and levers N an attachment, such as the swivelin O, to the valve-spindle P, so as to move 't e steam-valve E synchronously with the movement of the air-pump bucket G.

Having now described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

1. In a single-acting pump, the combination with a main steam-cylinder, of an auxiliary cylinder forming an extension of and of lesser diameter than the said main cylinder, and having an open lower end, a main piston or plunger fitting in said main cylinder, an auxiliary piston or plunger fitting in the said auxiliary cylinder, a pump-casing having a cover or upper extension H forming a chamber h separate from the ump-chamber and into which said pump-c amber discharges, said chamber h bein open at its top and communicating with t e chamber of the said open-ended auxiliary cylinder, and a pump P unger or piston operated from the said main and auxiliary pistons or plungers.

2. In a single-acting pump, the combination with a main steam-cylinder, of an auxiliary cylinder forming an extension of and of lesser diameter than the said main cylinder, and having an open lower end, a main piston or plunger fitting in said main cylinder, an auxiliary piston or plunger fitting in the said auxiliary cylinder, a pump-casing having a cover or upper extension H forming a chamber h separate from the pump-chamber and into which said pump-chamber discharges, said chamber it being open at its top and communicating with the chamber of the said open-ended auxiliary cylinder, a pump plunger or piston operated from the said main and auxiliary pistons or plungers, and a steam-valve operated from said pump piston or plunger.

3. In a single-acting pump, the combination with a main steam-cylinder, of an auxiliary cylinder forming an extension of and of lesser diameter than the said main cylinder, and having an open lower end, a main piston or plunger fitting in said main cylinder, an auxiliary piston or plunger fitting in the said auxiliary cylinder, a pump plunger or piston operated from the said main and auxiliary pistons or plungers, a steam-valve operated from said pump piston or plunger, and means for admitting a continuous supply of boilersteam to the lower face of said main piston or plunger.

In testimony whereof I have signed my name to this specification in the presence of;

two subscribing witnesses.

WILLIAM WEIR.

- Witnesses:

WALLACE FAIRWEATHER, JOHN MoCLEARY, Junr. 

